There are five programs, all for flaps in my RGC blog. These programs are all for 7 channel Rx's. You can probably use some or all of them in some form but you'll need to put the flaps on a Y extension and you will only have two position flaps. If you forgo flaperons/spoilerons you can have 3 position flaps.

You know, the more I think about my last post, the better it sounds. Except I'm gonna put one of the ailerons on the GEAR channel, and leave the flaps on the FLAP/AUX1 channel. That way, I minimize my 'Y' connections, and still get separate trim/etc. on the ailerons.

Seveeral approaches depending on how you want to use flaps and ailerons...

You can continue with the "flaperon" setup of one channel per aileron and plug flaps into any other switched or dial operated channel.
This may or may not limit the flaps to being 2 position. Depending on the plane this could be just fine.

You can mix the flaperon fucntion to the flaps and the flaps function back to the ailerons for more effects. Some planes I like to have ailerons come up 2 to 5 deg as flaps come down. it can make a plane that likes to violently tip stall n approach very docile.

The wonderful power of modern computer radios. Play with it. Test your experimental configurations with plenty of altitude and be ready to flip switches to put the plane back to a known safe setup.

You know, the more I think about my last post, the better it sounds. Except I'm gonna put one of the ailerons on the GEAR channel, and leave the flaps on the FLAP/AUX1 channel. That way, I minimize my 'Y' connections, and still get separate trim/etc. on the ailerons.

AIL->GEAR : +100% / +100%

I'm also setting my GEAR travel to 0%, JIC.

Not sure about your Dx7, but on my Dx8, if I wanted to do this I would have to disable my gear switch, or wierd things would happen. So if wierd things start happening when you try this, you may try that.

You know, the more I think about my last post, the better it sounds. Except I'm gonna put one of the ailerons on the GEAR channel, and leave the flaps on the FLAP/AUX1 channel. That way, I minimize my 'Y' connections, and still get separate trim/etc. on the ailerons.

AIL->GEAR : +100% / +100%

I'm also setting my GEAR travel to 0%, JIC.

You have to put this mix in P-Mix 5 or P-Mix 6 to have the aileron trim follow to the slave.

And as xmech2k said disable the gear switch. Do this with another P-Mix.